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Relative strength of the mitogenic and interleukin-2-production-inducing activities of staphylococcal exotoxins presumed to be causative exotoxins of toxic shock syndrome: toxic shock syndrome toxin-1 and enterotoxins A, B and C to murine and human T cells.

Several observations suggest that staphylococcal enterotoxins A, B and C (SEA, SEB and SEC, respectively), in addition to toxic shock syndrome toxin-1 (TSST-1), are causative exotoxins of toxic shock syndrome (TSS). Based on the view that polyclonal T cell activation with the causative exotoxins, resulting in over-production of lymphokines, is involved in the development of the pathological changes observed in TSS, we investigated the activities of these four exotoxins to induce proliferation and interleukin 2 production in murine and human lymphocytes by using in vitro culture systems. The results showed that all these exotoxins are strong polyclonal inducers of proliferation and interleukin 2 production in human T cells, whereas TSST-1 and SEA are strong and SEB and SEC are weak polyclonal inducers in murine T cells. These results suggest that SEA, SEB and SEC, in addition to TSST-1, are possibly involved as causative exotoxins in the development of the pathological changes observed in TSS.

Adult↗

Possible cytoskeletal association of 69,000- and 68,000-dalton heat shock proteins and structural relations among heat shock proteins in murine mastocytoma cells.

When murine mastocytoma cells (FMA 1) were heat shocked (42 degrees C for 4 h), nine heat shock proteins (HSPs) were detected by two-dimensional gel electrophoresis. Their apparent molecular weights were 100, 85, 69, 68, 32, 30, and 23 kDa (3 of 23 kDa). The structural homology of 4, 69, 68, 32, and 30 kDa, was demonstrated by two-dimensional tryptic peptide mapping. The 69- and 68-kDa HSPs were purified and rabbit antisera against these HSPs were prepared. A small fraction (less than 10%) of the 69- and 68-kDa HSPs were copurified with the microtubules and were present in the Triton X-100/KCl cytoskeletal fraction as shown by immunoblotting with the antiserum and by peptide mapping. Our results are consistent with the hypothesis of a cytoskeletal role for HSPs.

Animals↗

Effect of growth state and heat shock on nucleolar localization of the 110,000-Da heat shock protein in mouse embryo fibroblasts.

We have shown previously that the mammalian 110,000-Da heat shock protein (hsp110) associates with nucleoli in several cell types and that in 2-day postconfluent mouse 10T1/2 cells, a segregation of the antigen from the nucleolar phase-dense body is seen (J.R. Subjeck, T. Shyy, J. Shen, and R.J. Johnson. J. Cell Biol. 97: 1389-1395, 1983). Here we further characterize the nucleolar segmentation of hsp110 in mouse 10T1/2 and 3T3 cells with respect to the formation of this structure in dense cultures and investigate the behavior of this protein following conditions (serum deprivation, actinomycin D, and heat shock) known to affect the functional and morphological integrity of the nucleolus. It is shown that in addition to its nucleolar locale, an affinity of hsp110 for the nonnucleolar, nuclear compartment in actively proliferating cells is also observed. When proliferating cells are treated with actinomycin D (1 microgram/ml) for 8 h, hsp110 separates from the nucleolar phase-dense body to form a fluorescent nucleolar cap which resembles that seen in confluent cultures. This drug also results in a disappearance of hsp110 from the nucleoplasm. Incubation of cells for 24 h in media without serum also results in the nucleolar segmentation of hsp110 and a reduction in nucleoplasmic staining. A moderate nonlethal heat treatment does not lead to segmentation of hsp110 in proliferating cells but conversely results in a transient reversal of segmentation in confluent cultures. Examination of segmented nucleoli of postconfluent cells by immunoelectron microscopy reveals that hsp110 is associated with the fibrillar component of these nucleoli, the site of ribosomal DNA.

Animals↗

Imbalanced serum IgG subclass pattern in toxic shock syndrome patients: deficiency of specific IgG1 and IgG4 subclass antibodies to toxic shock syndrome toxin 1.

An imbalanced serum IgG subclass pattern was identified in 10 patients with toxic shock syndrome (TSS) showing remarkably low subclass levels of various combinations. IgG2 levels were significantly reduced as compared to normal controls. The IgG subclass-specificity of antibodies to toxic shock syndrome toxin (TSST-1) was investigated by a solid-phase radioimmunoassay. TSS-patients lacked pre-immunity to TSST-1 in all four IgG subclasses. Normally acquired immunity to the toxin as well as the serological response developing in two patients with TSS was generally restricted to IgG1 and IgG4. A strong booster response of all four IgG subclasses was seen in three patients with S. aureus septicaemia due to TSST-1 producing strains. The lack of specific IgG1 and IgG4 antibodies to TSST-1 and the low serum IgG subclass levels found in the TSS-patients could be of pathogenetic significance and help to explain the susceptibility to TSS in certain individuals.

Acute Disease↗

Toxic shock syndrome Staphylococcus aureus: effect of tampons on toxic shock syndrome toxin 1 production.

Tampons were tested for effect on growth and production of toxic shock syndrome toxin 1 by Staphylococcus aureus. Under good growth conditions, regular absorbency tampons had little effect on bacterial growth and inhibited toxin production two- to fourfold. In contrast, higher absorbency tampons had three different effects: 1) some tampons had no effect on bacterial growth but inhibited toxin production; 2) many tampons inhibited both growth and toxin production; 3) one tampon inhibited growth but increased exotoxin per cell. These effects were independent of degree of saturation of the tampons and were observed at incubation times of six, 12, and 18 hours. In no instance was the production of toxic shock syndrome toxin 1 per milliliter increased in the presence of tampons when compared with control.

Absorption↗

The shock liver. Clinical and biochemical findings in patients with centrilobular liver necrosis following cardiogenic shock.

Five patients with severe heart disease developed cardiogenic shock of more than 24 hours' duration. As a sequela to the shock, severe liver affection was demonstrated. Serum aspartate aminotransferases and serum lactate dehydrogenases showed very high activities. The prothrombin-proconvertin index was reduced to less than 25% of the normal. Four of the patients were jaundiced. The condition gave rise to some differential diagnostic problems. Liver biopsies were available from four of the patients, and histological examination of an autopsy specimen of the liver was performed in each case. The liver histology showed centrilobular necrosis and haemorrhage in all patients. It seems that centrilobular fibrosis develops later in the condition. The pathogenesis of this liver affection is probably hypoxic injury to the centrilobular areas of the liver lobule due to reduced liver blood flow.

Aged↗

The heat shock response and major heat shock proteins of Tritrichomonas mobilensis and Tritrichomonas augusta.

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.

Animals↗

[Septic shock in the uroseptic patient. I. General and specific pathomechanisms of the septic shock (author's transl)].

Failure of microcirculation in septic shock is due to the generalized release of catecholamins following a fall in cardiac output by the activity of bacterial toxin. The failure of the microcirculation can be defined as 1. a failure of the distribution of the tissue perfusion, and 2. a decrease of capillary flow due to obstructed inflow, reduced capillary flow passage and obstructed outflow. Bloodviscosity increases because of fluid sequestration, aggregation of rbc's and decrease in velocity of the blood flow. All this results in a dispariaty of oxygen consumption and availability to the tissue. The characteristics of specific organ disturbances in shock go along with the distribution of the alpha-receptors in each organ, the specific physiological function and architecture of the organ as well as previous diseases of the organ.

Angiotensin II↗

Interaction between Arabidopsis heat shock transcription factor 1 and 70 kDa heat shock proteins.

The activity of the Arabidopsis heat shock transcription factor (HSF) is repressed at normal conditions but activated by cellular stresses. Circumstantial evidence suggests that HSP70 may function as a negative feedback regulator of HSF activity. Here the interaction between HSF and HSP70 is reported using electrophoretic mobility shift and yeast two-hybrid assays. Subdomain mapping indicates an interaction of the activation domain and DNA-binding domain of HSF1 with HSP70.

Arabidopsis↗

Heat stress-dependent DNA binding of Arabidopsis heat shock transcription factor HSF1 to heat shock gene promoters in Arabidopsis suspension culture cells in vivo.

Using UV laser cross-linking and immunoprecipitation we measured the in vivo binding of Arabidopsis heat shock transcription factor HSF1 to the promoters of target genes, Hsp18.2 and Hsp70. The amplification of promoter sequences, co-precipitated with HSF1-specific antibodies, indicated that HSF1 is not bound in the absence of heat stress. Binding to promoter sequences of target genes is rapidly induced by heat stress, continues throughout the heat treatment, and declines during subsequent recovery at room temperature. The molecular mechanisms underlying the differences between Hsp18.2 and Hsp70 in the kinetics of HSF1/promoter binding and corresponding mRNA expression profiles are discussed.

Arabidopsis↗

Heat shock proteins and heat shock protein-antibody complexes in placental tissues.

OBJECTIVE: The relationship between pregnancy outcome and expression of the heat shock proteins (hsps) or hsp-antibody complexes of 60kD (hsp60), 70kD (hsp70), and 90kD (hsp90) in placental tissue and circulating antibodies to hsps was evaluated. METHOD: Expression of hsp60, hsp70, and hsp90 in placentae from 12 women with preterm birth, eight with intrauterine growth restriction (IUGR), and 10 with term birth, as well as the presence of the corresponding antibodies, was investigated by a new carbocyanine double fluorescence technique. Results were compared with microbiological findings and circulating antibodies to hsps in sera. RESULTS: In each placental specimen examined, hsp60, hsp70, and hsp90 were identified. However, hsp70-antibody complexes were detected in only four of the preterm labor cases. Similarly, hsp60-antibody complexes were detected in only five preterm labor patients and in one patient with IUGR. None of the placentae contained hsp90-antibody complexes. In the preterm birth group, all patients with hsp60-antibody complexes were also positive for circulating antibodies to hsp60. The presence of hsp70-antibody complexes also correlated with hsp70 antibody in sera. CONCLUSIONS: Formation of hsp60- and hsp70-antibody complexes in the placenta may contribute to the induction of preterm birth. Women sensitized to these antibodies may be at increased risk for adverse pregnancy outcome.

Antigen-Antibody Complex↗

Involvement of calcium in the differential induction of heat shock protein 70 by heat shock protein 90 inhibitors, geldanamycin and radicicol, in human non-small cell lung cancer H460 cells.

Both geldanamycin (GA) and radicicol (RA) are HSP90 binding agents that possess antitumour activities. Although the in vitro data indicated that the inhibitory constant of RA is much bigger than that of GA, the in vivo data on drug efficacy might reveal different results. We have recently shown that treatment with GA induces a heat-shock response and that calcium mobilization may be involved in the process. By using induction of HSP70 as the endpoint assay, we found changes in upstream signaling mediators, including HSF1 and calcium mobilization, as well as possible involvement of protein kinase in human non-small cell lung cancer H460 cells treated with GA and RA. Our results demonstrated that calcium mobilization, a calcium dependent and H7-sensitive protein kinase, along with HSF1 activation by phosphorylation, are all involved in the HSP70 induction process triggered by the drugs. However, only GA, but not RA, can provoke a rapid calcium mobilization and thereby result in an instant induction of HSP70. Furthermore, the rapid calcium influx, followed by instant HSP induction, could be achieved in GA- or RA-treated cells placed in a medium containing excessive calcium while the response was completely abolished in cells depleted of calcium. Taken together, our findings suggest that differential calcium signaling may account for the differential induction of HSP and the action of GA and RA.

Benzoquinones↗

Polymorphism in the regulatory sequence of the human hsp70-1 gene does not affect heat shock factor binding or heat shock protein synthesis.

A bi-allelic polymorphism found in the regulatory region of the human heat shock (HS) protein (HSP) hsp70-1 gene, which comprises an A-->C transversion, 3 bp upstream of the HS element (HSE), has been associated with extended HLA haplotypes. In view of the chaperoning and protective functions of Hsp70, we investigated whether this hsp70-1 bi-allelic polymorphism could modulate the stress response, which may relate to enhanced resistance or susceptibility to certain diseases. We compared the basal and HS-induced HS factor (HSF)-binding activity of the two polymorphic HSEs, hsp70-1 mRNA accumulation and HSP expression in two human Epstein Barr virus (EBV)-transformed B cell lines typed for hsp70-1 promoter alleles. Our results suggest that hsp70-1 promoter polymorphism does not influence HSF-binding activity, hsp70 mRNA accumulation or synthesis in human EBV-transformed B cell lines.

Alleles↗

High calcium induces heat shock proteins 72 and 60 in cultured human keratinocytes: comparative study with heat shock and sunlamp light irradiation.

Expression/induction of the 72 and 60 kDa heat shock proteins (HSPS 72 and 60) in cultured human keratinocytes by high calcium was studied with immunofluorescent staining and the flow cytometric method. Normal human keratinocytes cultured in serum free, low calcium medium (Ca2+, 0.1 mM) at 3-passage weakly expressed HSP 60, but not HSP 72, as fine granules in the cytoplasm. HSP 72 was induced in the perinuclear cytosomal area and then in the nucleus after transferring the cells in high calcium medium (Ca2+, 1.8 mM). Whereas the nuclear accumulation began to decrease 24 h after the treatment, the perinuclear cytosomal staining continued. High calcium also augmented the expression of HSP 60 as coarse granules in the cytoplasm. Flow cytometric analyses quantitatively revealed the induction of HSP 72 and the upregulation of HSP 60 by high calcium treatment. Our results clearly demonstrated that extracellular calcium concentration modifies the level of expression of HSP 72 and 60 in normal human keratinocytes, indicating the importance of the careful attention to medium condition in evaluating the expression of HSPS 72 and 60 in cultured keratinocytes.

Calcium↗

Mediator, not holoenzyme, is directly recruited to the heat shock promoter by HSF upon heat shock.

Activators of RNA polymerase II (Pol II) transcription have been shown to bind several coactivators and basal factors in vitro. Whether such interactions play a primary regulatory role in recruiting these factors to activator-associated chromosomal target sites in living cells remains unclear. Here, we show that upon heat shock the Pol II-free form of Mediator is rapidly recruited to HSF binding sites. Unlike the TAFs and Pol II, the interaction between Mediator and HSF on chromosomal loci is direct and mechanistically separable from the preinitiation complex assembly step. Therefore, the activator-Mediator interaction likely underlies the initiation of signal transfer from enhancer-bound activators to the basal transcription machinery.

Amanitins↗

Heat shock treatment suppresses angiotensin II-induced activation of NF-kappaB pathway and heart inflammation: a role for IKK depletion by heat shock?

Heat shock (HS) proteins (Hsps) function in tissue protection through their chaperone activity and by interacting with cell signaling pathways to suppress apoptosis. Here, we investigated the effect of HS treatment on the nuclear factor (NF)-kappaB signaling pathway in the angiotensin II (ANG II) model of inflammation. Male Sprague-Dawley rats were divided into sham and HS-, ANG II-, and HS + ANG II-treated groups. HS treatment was administered 24 h before the initiation of ANG II infusion. HS treatment (42 degrees C for 15 min) decreased 7-day ANG II-induced hypertension from 191 +/- 4 to 147 +/- 3 mmHg (P < 0.01). Histological staining of hearts showed that HS treatment reduced ANG II-induced leukocyte infiltration, perivascular and interstitial inflammation, and fibrosis. Heart NF-kappaB nuclear translocation and activity, examined by Western blot analysis and electrophoretic mobility shift assay, was suppressed by HS treatment. HS treatment depleted IkappaB kinase-alpha (IKK-alpha) and phosphorylated IKK-alpha and suppressed the depletion of IkappaB-alpha and the accumulation of phosphorylated IkappaB-alpha. HS treatment blocked ANG II induced expression of IL-6 and ICAM-1 in the heart. ANG II and HS treatment induced high-level expression of Hsp27 and Hsp70 and their phosphorylation. Phosphorylated isoforms of Hsp27 and Hsp70 may play an important role in protecting the heart against ANG II-induced inflammation.

Angiotensin II↗

Heat shock protein 27 associates with basolateral cell boundaries in heat-shocked and ATP-depleted epithelial cells.

Heat stress alters epithelial barrier function, and heat stress preconditioning protects epithelial function from injury. Hsp27 is a small stress protein that has previously been shown to modulate actin assembly. Thus, by regulating actin filaments associated with cell junctions, hsp27 could alter epithelial function. To begin to address this hypothesis, the regulation and distribution of a human hsp27-green fluorescence fusion protein ((EGFP)hHsp27) that is expressed in cultured renal epithelial cells was assessed. (EGFP)hHsp27, like the endogenous hsp27, associated with the cytoskeleton in heat-stressed and chemically ATP-depleted cells, and both proteins were regulated similarly. Confocal microscopy of intact and detergent-lysed cells revealed novel distribution patterns in which (EGFP)hHsp27 associated with basolateral, but not apical, cell borders in injured cells. Double labeling studies revealed (EGFP)hHsp27 and actin filament colocalization in ATP-depleted cells. However, during heat shock, granules of (EGFP)hHsp27 were found at sites of cell-cell contact and in the cell body, but colocalization with actin was not apparent. Thus, heat stress and ATP depletion induce distinct patterns of hsp27 redistribution in epithelial cells, and sites of cell-cell and cell-substrate attachment are unique in their ability to recruit hsp27 during injury. The association of (EGFP)hHsp27 with basolateral cell boundaries supports a potential role for hsp27 in protection or regulation of epithelial cell-cell and cell-substrate attachments.

Adenosine Triphosphate↗

Heat shock gene expression during recovery after transient cold shock in Drosophila auraria (Diptera: Drosophilidae).

Newly synthesized polypeptides during recovery from prolonged cold treatment (0 degree to -1 degree C) of Drosophila auraria, a montium subgroup species, of the melanogaster species group, were analysed in denaturing polyacrylamide gels. In addition, during the cold shock recovery period, Northern analysis of the hsp83 mRNA was performed. A significant induction of two polypeptides, which exhibited electrophoretic mobilities, with the heat inducible 83 and 70 kD hsp83 and hsp70 was detected, but no such induction was evident in the so-called 'small' hsp genes. These results are compared and discussed with those observed in D. melanogaster.

Animals↗